Elsevier

Clinical Colorectal Cancer

Volume 6, Issue 10, November 2007, Pages 716-719
Clinical Colorectal Cancer

Original Contribution
Intensity-Modulated Radiation Therapy for the Treatment of Anal Cancer

https://doi.org/10.3816/CCC.2007.n.041Get rights and content

Abstract

Purpose

The aim of this study was to assess whether intensity-modulated radiation therapy (RT; IMRT) can reduce dose to normal tissues (organs at risk) while maintaining equivalent target coverage.

Patients and Methods

A 9-field, non-coplanar, 1-cm beamlet IMRT plan was designed for 9 patients who were previously treated for anal cancer with conventional field arrangements. Clinical target volumes and organs at risk (OARs) were defined. Target coverage was assigned highest priority for optimization, followed sequentially by organ at risk. The genitalia and perineal skin were the highest priority OARs. Lexicographic ordering–based IMRT optimization was used to generate a conformal plan, which was compared with the conventional, previously delivered RT plan.

Results

The IMRT and conventional RT plan achieved homogeneous dose coverage of all target volumes. Intensity-modulated RT produced highly conformal dose distributions compared with conventional techniques, with avoidance of critical normal structures. Statistically significant reductions in mean doses to the perineal skin and to the genitalia were seen with IMRT, with only a modest increase in mean dose to the bony pelvis.

Conclusion

Intensity-modulated RT, with lexicographic ordering, allows for substantial reduction of dose to OARs while maintaining adequate target coverage. These encouraging findings might translate into reductions of treatment-related toxicity, gains in local control, or improvements in quality of life.

References (20)

There are more references available in the full text version of this article.

Cited by (21)

  • Gastrointestinal

    2020, Proton Therapy: Indications, Techniques and Outcomes
  • Radiotherapy for anal canal cancers

    2016, Cancer/Radiotherapie
  • Initial Report of Pencil Beam Scanning Proton Therapy for Posthysterectomy Patients with Gynecologic Cancer

    2016, International Journal of Radiation Oncology Biology Physics
    Citation Excerpt :

    Strategies to limit the bone marrow dose using intensity modulated radiation therapy (IMRT) have been evaluated, with recent studies demonstrating that the volume of PBM receiving 10 and 20 Gy (V10, V20, respectively) is significantly associated with the development of acute hematologic toxicity in women receiving concurrent platinum-based chemotherapy (7, 8). One of the potential consequences of bone marrow sparing using IMRT is greater incidental doses to other organs at risk (OARs), because the beam angles and dose constraints chosen to avoid high doses to the bone marrow will result in consequently higher doses to other OARs (9). The physical characteristics of protons allow for irradiation of the target with a minimal exit and integral dose, which might result in lower collateral irradiation to normal structures (ie, bone marrow, bowel) compared with IMRT (10, 11).

  • Organ-sparing Intensity-modulated Radiotherapy for Anal Cancer using the ACTII Schedule: A Comparison of Conventional and Intensity-modulated Radiotherapy Plans

    2013, Clinical Oncology
    Citation Excerpt :

    We consider IMRT1 to be the best compromise to meet our conditions to: (a) adhere to standard UK radiotherapy practice with respect to dose and target volume and (b) minimise the effect that a possible change in practice may have on clinical departments. Our IMRT technique is less complicated than those reported by other investigators as we only use seven beams spaced at variable angles compared with eight to10 equally spaced beams [6,17,18]. This may be due to the smaller target volumes and lower prescription dose.

  • Clinical target volumes in anal cancer: Calculating what dose was likely to have been delivered in the UK ACT II trial protocol

    2012, Radiotherapy and Oncology
    Citation Excerpt :

    Results showed improved local control, overall survival and reduced acute and late toxicity, but patients receiving 3D conformal radiotherapy had treatment over 6 weeks continuously as opposed to 8–12 weeks (split course) in patients receiving conventional treatment, i.e. shortening the overall treatment time. With IMRT, radiation dose to OARs is reduced compared with conventional 2D and more sophisticated 3D treatment planning [23–25]. Pilot studies (single centre and multicentre) have been conducted which have shown IMRT to be well tolerated with mild to moderate acute symptoms, and few patients experiencing treatment breaks [26,27].

View all citing articles on Scopus

Electronic forwarding or copying is a violation of US and International Copyright Laws.

Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by CIG Media Group, LP, ISSN #1533-0028, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400.

View full text